/in/foo.cc: In function 'int main()':
/in/foo.cc:21:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |         for (int j = 0; j < numbers.size(); ++j) {
      |                         ~~^~~~~~~~~~~~~~~~
/in/foo.cc:29:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     for (int i = 0; i < numbers.size(); ++i) {
      |                     ~~^~~~~~~~~~~~~~~~